The Evolution Law And Forecast Of Temperature In Lanzhou City

In the past 100 years,the global climate is undergoing significant changes characterized by global warming.The temperature change in China is generally consistent with that in the world,but slightly different in different regions.Lanzhou is located in the northwest of China.Temperature is the basic index of weather forecasting,and improving the accuracy of temperature forecasting is very important for human life.By using local polynomial fitting analysis in lanzhou city,quarterly,monthly mean minimum temperature,mean maximum temperature,average temperature change of long-term trend,using PB breakpoint test analysis lanzhou discontinuity point temperature changes,and with a separation method at different stages of mutations in lanzhou city,quarterly,monthly mean minimum temperature,mean maximum temperature,average temperature changing rate to reveal lanzhou city air temperature change rule,the following conclusions:(1)The lanzhou city temperatures were significantly increased volatility trend,and heat up the fastest in the 80 s.(2)The changes of high temperature and low temperature in lanzhou have obvious asymmetry.The specific performance is that the highest temperature has a strong fluctuation and a small increase,while the lowest temperature has a relatively single change and a large increase.(3)There is no obvious periodicity of temperature change in lanzhou.Specifically,the abrupt temperature change years were around 1960,1970,1983 and 2000,and the temperature change rate in different stages was not consistent.(4)The temperature changes in lanzhou are different in different seasons and months.Compared with other seasons,lanzhou's winter warming trend is more obvious.Temperatures rose more in January,February and December than in any other month.At present,temperature series are mostly used as a whole in temperature prediction research,and the separation of long-term trend,periodicity and residual residual term is not realized,which is difficult to meet the requirement of prediction accuracy.In this paper,b-spline function is used to fit the long-term trend of temperature evolution,Fourier series is developed to fit the periodic components in the temperature sequence,and QAR model is used to fit the zero mean residual sequence after removing the long-term trend and periodic components in the original sequence,and a combined temperature prediction model based on b-spline-fourier-QAR is constructed to predict the temperature.By analyzing the precision of temperature prediction under different prediction steps,it is found that the temperature combination prediction precision based on b-spline-fourier-QAR is higher.